Medium pressure ductwork

[Kmann444]

How is medium pressure air reduced to low pressure
I saw a installation where they used a pneumatic air valve to reduce pressure to low pressure . The work was done 40 years ago .I was wondering if this is still the way to go on an alteration

 

[GT-EGR]

Still would be done the same way, using a damper or a VAV box which is basically an automatic damper to drop the pressure and regulate flow quantity before it is discharged into the space. Or you said valve which in a critical space is a particular type of Venturi which again just reduces the pressure and regulates flow.

Except now you usually don’t use pneumatics to automatically control, you use a DDC controller which just uses low voltage power instead of pneumatic air.

We’d have to know what kindof alteration and what your system is, but generally VAV is very widely used and likely still makes sense. Also anytime you can operate at low pressure there are a lot of benefits, mainly downstream of the valve it’s done for noise and because there isn’t that much pressure actually needed to get through a properly designed air outlet.